Explosive composition



Patented June v19, 1934 EXPLO SIV E COMPOSITION Karl T. Gent, Terre Haute, Ind., and Norman G. Johnson, Woodbury, N. J., asslgnors to E. I. du

Pont de Nemours &

C mpany. Wilmington,

Del., a corporation of Delaware No Drawing. Application February 2:, 1932,

Serial No. 594,734 W V 14 Claims. (01. 52-11) This invention relates to an improvement in explosive compositions having a liquid explosive ingredient as a sensitizing agent, and in particular to such a composition of the permissible dyna- 5 mite type including a carbonaceous combustible material comprising certain selected parts of cereal grains.

Low density dynamites have assumed a position of particular importance in recent years.

The advantages of these explosives are many in the blasting of materials having relatively low resistance such for example as coal, salt, and soft rock. Since by such means the distribution of the strength of the explosive over a considerable bore hole surface is effected, and at the same time undue shattering of the material to be blasted is in a great measure prevented. These and numerous other advantages of low density dynamite compositions of the several types are well known in the art.

Low density dynamites have heretofore been produced by a variety of means and compositions, important among which are such carbonaceous combustible ingredients as bagasse pith, balsa as wood, ground cornstalks, popped corn and like materials.

An object of this invention is a further improvement in explosive compositions. A particular object is to provide a low density dynamite containing as an element of the composition a combustible ingredient of an improved character. A further object of our invention is a low density dynamite havingimproved sensitiveness properties and one in which the combustible material 5 has relatively low absorbent properties for liquid explosive ingredients, such for example as nitroglycerin. A further object of our in'ventionis an explosive product containing as an ingredient a flaked cereal product. Other and further objects 0 will suggest themselves as our invention is more fully described hereinafter.

Our invention comprises broadly the use in commercial explosives, for example dynamite, of a.

class of cereal products not heretofore used in explosives and which have been so treated as to be converted into the form of low density flakes. Cereals and cereal products, such as corn, wheat, rye, starch, hominy grits, etc., can be converted into low density flakes by various processes. The 5 one most commonly used and the one which will be described in detail hereinafter is known as the dry process of milling", as distinguished from the preparation of starch which involves what is known as the wet process".

In the dry process of milling as applied generally to maize the hulls-and germs are removed and the grains broken into pieces, cooked by steam or other suitable means and pressed to form flakes. This dry process is accomplished by first tempering" the grains which consists in softening them by means of a small amount of water, thistreatment requiring usually from 3 to 4 hours. At the end of the soaking period live steam is injected into the material. The product is then passed to a degerminator which breaks 66 up the grain, releasing the germ, the hull, and the softer portion of the starch which surrounds the germ. In this degerminating process the horny portion of the maize kernel is usually cracked or broken into several pieces. It is this 70 horny portion that is most suitable for producing low density flakes. Other starchy portions of course may be flaked by themselves or in combination with the horny portion properly reduced to uniform size. The germ of the cereal grain contains a substantial amount of oil and for this reason it is desirable to remove this from the horny material before flaking.

The resulting material, which at this point may be termed crude hominy", is then subjected to so a cooking process which is intended primarily to slightly soften and preheat the grain before entering the next step in the process. In this cooking process the temperature of the crude hominy is usually raised to approximately 200 35 to 250 F. The hot, moist material is then subjected to high pressure, for example, by passing through heavy rolls. These rolls operate at a relatively high temperature and the thus treated grains in passing through the rolls are converted go into a stiff cohesive flake or sheet. e

If the product from the hot rolls is in the form of flakes or sheets then in order to convert these flakes or sheets into proper form for our purpose it is necessary to subject them to a rough grinding process in order to reduce the flakes or sheets to smaller particles suitable for mixing with other explosive ingredients. Flakes of a size suitable for direct use in explosives can be produced provided the grain particles known as grits are sufflciently small in size. We have found that a suitable material is a size that a major portion will pass a G-mes'h screen and at the same time be held on a 60-mesh screen.

There are many variations in the process described in the foregoing, both in the preliminary preparation of the grain and in the handling of the material from the rolls. The-essential features of the process however lie in passing a treated cereal or cereal product through hot rolls d in order to convert it into flakes. There are other processes for producing flaked cereal products. For example, another type of process comprises delivering the moist cereal product to a hot roll rovided with a scraper where the product is dried and gelatinized and removed from the drum by the scraper. Such processes are well known in the art.

It will be seen at once that this material diflers substantially irom popped corn covered by Johnson and Baker U. 8. Patent 1,687,023, and from properties over similar compositions notwith= standing the fact that some other ingredients have equally low density. The treated or ilaked cereal products accordingto this invention exhibit the unique property at producing low density nitroglycerinexplosives oi greatly i proved sensitiveness or propagating power as compared with similar explosives but containing other low density carbonaceous material'such for example as bagasse pith, balsa wood. etc. This cereal product is oi particular value in the case of permissible dynamites which at best are nohe too sensitive to detonation ando! which the lowering or the density by the use of the usual low density absorbents is accompanied'by a serious loss in sensitiveness. We have found furthermore that this'iinproved sensitivenesuis due to the fact that the combustibl material, while low in density, does not readily absorb nitroglycerin or other liquid explosive ingredients that may be present in the composition.

Our invention is applicable to all non-gelatfinous types of dynamite compositions, of which the three main classes are commonly known as straight ihmamites, ammonia dynamltes, and permissible dynamites. The straight dynamtes are made in strengths varying from about 20% to 75% and are used in blasting work where high velocity and sensitiveness to detonation are essential. Ordinarily they comprise a liquid explosive ingredient in a percentage equal to their grade strength, combustible abmrbents and sodium nitrate. The ammonia dynamites are likewise made in averal strengths and are used in general'blastirg work. They comprise a lower percentage of liquid explosive than the straight dynamite's of similar grade, ammonium nitrate,

sodium nitrate and combustible absorbent-s. The

20 ammonia dynamite, for example, may con tain 10 to 15% of liquid explosive and 8 to 15% ammonium initrate, while the 60% ammoniadynamite may have 15 to 30% of liquid explosive and 45 to 60% ammonium nitrate. The permissible dynamites are ordinarily o! high grade strength, from 40 to and are intended for use in coal mines where there is danger of explosion from minegases and coal dust. These permissible dynamites contain relatively low per-,

centa'ges of liquid explosive, usually between 8 and 15%, and relatively high percentages of ammonium nitrate, 50 to 86%, combustible absorbents, and, in many cases, inorganic salts for the purpose of reducing the flame temperature, sodium chloride or sodium nitrat for example.

While our invention is applicable to many difierent forms of explosives, the following examples'are given to illustrate its applicability to each of the types of dynamite compositions described in the foregoing:

Ingredient Percent. Percent. Percent.

N itroglyoerin so 23 i0 Ammonium nitrate. 52 75 B cdium nitrate in i4 6 Flaked com product 6 2 it Other combustible l5 9 2 In addition to the improvement in other properties, the low density ei'lect oi the use oi! our new combustible ingredients is shown by the fact that it makes possible the production of straight and ammonia dynamites on otherwise standard formulas, weighing less than 181 grams per 1% x 8" cartridge, against a weight OM10 to did) grams ordinarily obtained. Similarly with dynaniites or the permissible type, our new ingredient makes'it possible to obtain weights of 1% x 8" cartridges of less than 146 grams, much lower densities being possible with complete utilization oi the treated and expanded corn product described in the ioregoing. 7

Various amounts of ,our improved ingredients may be wed in dynamite compositions with setisfactory results. It will be apparent from the foregoing that the higher the percentages we use. replacing the heavier ingredients, the lower will be the density oi? the finished explosive. While amounts greater than '20 per cent.'may be" used, the higher percentages have the disadvantage of adding too much carbonaceous combustibles to the, explosive. We flnd also that amounts less than one per cent. are insuiilcient to have any appreciable shoot on either-the density or the between 2 and .12 per cent.oi our flaked maize product. The use of at least 5 per cent. of liquid explosive ingredient is desirable in our new explosive composition, in the absence of other explosive sensitizers, since a smaller amount than this results in an explosive insufficiently sensitive for satisfactory use.

It will be understood, of course, that the percentages oi! ingredients given in the foregoing examples may be varied within wide limits, and that additional ingredients may be introduced without departure from'the spirit of the invention. Qui' invention thereiore contemplates the use of these low density ingredients as the sole combustible material, or L1 combination with other combustible ingredients. The other combustible ingredients may be either high density or low density ingredients. For example, it is contemplated that our new explosive may have inset rated therein other low density ingredients such as bagasse pith, balsa wood, popped corn, etc. We may use also in place of nitroglycerin for example, solutions in. nitroglycerin of various materials conmonly considered as freezing point depressants, nitroglycol, intrated polymerized glycerin, nitrated sugars, nitrocompounds, etc. The amount of sodium nitrate may likewise be increased or decreased as desired, or omitted entirely, in which case sodium chlorideor other flame suppressing material may be used.

Accordingly, it is to be understood that wears to be limited in our invention as indicated in the follow g patent claims.

We claim:

1. A dynamite composition which comprises a liquid explosive ingredient and a flaked cereal product.

2. A dynamite composition which comprises a liquid explosive ingredient and a degermed flaked cereal product.

3. A dynamite composition which comprises a liquid explosive ingredient and a flaked cereal product having a density between 0.1 and 0.2.

4. A dynamite composition which comprises a liquid explosive ingredient, and a carbonaceous combustiblematerial comprising a flaked maize product from which the germ and hull portions have been removed.

5. A dynamite composition which comprises a degermed flaked cereal product and at least 5% of a liquid explosive ingredient.

6. A dynamite'composition which comprises a liquid explosive ingredient and 1% to 20% of a flaked cereal product.

7. An explosive composition of the permissible type characterized by its low density which comprises a liquid explosive ingredient, an inorganic nitrate, a non-explosive salt adapted to reduce flame temperature, and a flaked maize product.

8. An explosive composition of the ammonium nitrate permissible type containing as an ingredient a flaked maize product, said composition having a density such that a 1 x 8" cartridge weighs less than 146 grams.

9. An explosive composition of the straight dynamite type comprising a liquid explosive ingredient and containing a flaked maize product, said composition having a density such that a 1%" x 8" cartridge weighs less than 181 grams.

10. An explosive composition of the ammonia type comprising a liquid explosive ingredient, ammonium nitrate, and a flaked maize product, said composition having a density such that a 1%" x 8" cartridge weighs less than 181 grams.

11. A low density explosive composition comprising a liquid explosive ingredient, and gelatinized corn flakes.

12. A low density explosive composition comprising a liquid explosive ingredient, and gelatinized cereal flakes cut to desired size.

13. A low density explosive composition comprising a liquid explosive ingredient, ammonium nitrate, a non-explosive salt for reducing the flame temperature, and gelatinized cereal flakes.

14. A low density explosive composition of the permissible type comprising a liquid explosive ingredient, ammonium nitrate, sodium nitrate, and gelatinized corn flakes.

KARL T. GENT. NORMAN G. JOHNSON. 

